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A quick way to sort and measure such complicated spectra is to apply FFT. FILMeasure contains a suite of advanced tools to simply this analysis including: FFT Window Function, intelligent selection of wavelength range, and optical smoothing. We’ll also deal with the effects of measurement spot size and instrument selection.

2023年3月2日 · FILMeasure 软件包括一系列高智能方法来简化光谱分析。 这包括FFT 窗口功能，波长范围自动优化， 以及光学厚度滤波。 我们会讲到光斑尺寸的影响以及设备的选配。 还会讲到多层薄膜的应用。 Copyright © 2025 KLA Corporation. All Rights Reserved.

A fast Fourier transform (FFT) is an algorithm that computes the discrete Fourier transform (DFT) of a sequence, or its inverse (IDFT). A Fourier transform converts a signal from its original domain (often time or space) to a representation in the frequency domain and vice versa.

2019年7月4日 · In this paper we discuss how these deviations affect the thickness determination and present a solution for the main problem caused by the dispersion of the refractive index. Further improvements of the FFT result in combination with a grid search algorithm and a nonlinear regression are presented and discussed.

Actually, the main uses of the fast Fourier transform are much more ingenious than an ordinary divide-and-conquer strategy— there is genuinely novel mathematics happening in the background. Ultimately, the FFT will allow us to do n computations, each of which would take (n) time individually, in a total of (nlgn) time.

Fast Fourier Transform History Twiddle factor FFTs (non-coprime sub-lengths) 1805 Gauss Predates even Fourier’s work on transforms! 1903 Runge 1965 Cooley-Tukey 1984 Duhamel-Vetterli (split-radix FFT) FFTs w/o twiddle factors (coprime sub-lengths) 1960 Good’s mapping application of Chinese Remainder Theorem ~100 A.D. 1976 Rader – prime length FFT

Y = fft(X) computes the discrete Fourier transform (DFT) of X using a fast Fourier transform (FFT) algorithm. Y is the same size as X. If X is a vector, then fft(X) returns the Fourier transform of the vector. If X is a matrix, then fft(X) treats the columns of X as vectors and returns the Fourier transform of each column.

Film Metrology Systems The SpectraFilm™ F1 film metrology system helps achieve strict process tolerances at sub-7nm logic and leading-edge memory design nodes by providing high-precision thin film measurements for a broad range of film layers.

2020年8月12日 · Thicker films (>8um) produce a lot of optical fringes. A quick way to sort and measure such complicated spectra is to apply FFT. FILMeasure contains a suite of advanced tools to simply this analysis including: FFT Window Function, intelligent selection of wavelength range, and optical smoothing.